How can I tell if a conference is in use?

I have several conferences set up here and a larger number of teams who will want to use the conferences from time to time. Each conference is (and must be) set up to allow anyone, and any number of participants, to enter.

Is there a way that somebody who is looking for a free conference to use can detect if a conference is in use, without actually calling in to it and detecting that there are people talking there?


I would use FOP2 for that.